Distillation of tar



Aug. 29, 1933. sg. P. MILLER DISTILLATION 0F TAR Filediu'a'ron 23, 192523l 4 sheets-sneek 1 VENTOR ATTORNEYS S. P. MILLER DISTILLATION` OF TAR Aug.f29, 1,933.

Filed March 25, ,1928

4 Sheets-Sheet 2 w l INVENTOR BY 7 -TORNEYS Agg. 29, A1933. s. P. MILLER DISTILLATION OF TAR Filed March 23, 1928 4 Sheets-Sheet 5 ATTORNEY INVENTO' AMM "mi il Aug. 29, 1933. s. P. MILLER DISTILLATION oF TAR Filed March 2s, 1928 4 Sheets-sheet 4 Patented Aug. 29, i933 f l 1,924,163

UNITED STATES PATENT OFFICE DISTILLATION F TAR i Stuart Parmelee Miller, Englewood, N. J., as-

signor to The Barrett Company, New York, N. Y., a Corporation of New Jersey Application March 23, 1928. Serial No. 263,989

3 Claims. (Cl. 202-30) This invention relates to improvements in the serves to remove therefrom to a greater or less distillation of tar, tar oils and pitches and inextent the entrained tar and pitch c0nstituents, cludes a new method of distillation as well as an leaving relatively clean gases at a high temperaimproved apparatus therefor. Although the inture 'for use in the distillation. When these rela- 5 vention is applicable to the distillation of tar tively clean and still hot gases are so employed 60 with gases from other coal carbonization and gasi- Vfor distillation, the distillatefrom-the still, which cation operations, it will be described more paris admixed with the gases employed for the disticularlyas applied to coke oven operations. tillation, and which is subsequently recovered In the ordinary operation of by-product coke therefrom by cooling and condensation, will be a l0 ovens, the gases produced by the coking operarelatively clean distillate, 'i. e., relatively free 65 tion pass from the individual ovens through upfrom the heavy tar and pitch constituents initialtake pipes and goose-necks. to a collector main ly entrained in the gases. common to the ovens of the battery. The gases, The cleaning of the hot coal distillation gases commonly known as foul" gases, leave the ovens according to the present invention is carried out at high temperatures, for example at 600D to at the required temperature and Without reduc- 700" C., or higher, and carry a considerable pro- IOII 0f tempratllle 0f the gaSeS- Cleaned below portion of pitchy material, iai-s and oils as weil that at which they are to be used for subsequent as solid particles of coke` dust, etc. Ordinarily, distillation. This scrubbing of the gases may be the gases are cooled by the application of sprays effected with or without distillation of the scrubof ammonia liquor or ammonia liquor and tmin bing medium. The scrubbing medium may be the collector main, or by Circulating ammonia preheatedv to a temperature approaching that of liquor and tar through the main, the heat in the the gases scrubbed or it may be at a lower temgases being thereby dissipated and lost The perature. The scrubbing operation should be cooling causes separation o'f tar containing heavi- Sumciently Complete t0 'remove from the gases er oils in the collector main. Further cooling is .Completely 0r t0 the desired extent the entraned effected in the oross ov@1 main which Connects pitch or tar constituents, leaving the gases still the collector main to the condensing system and at the required temperature; Counter'cufrent an additional quantity of tar carrying both heavy scrubbers which brlng about intimate contact of and lighter oils is thus separated. In the coolthe gases with the srubbmghquld can be em' 35 ers or condensers tairy Oils are separated. The ployed' The SCrubbmg hqmd. may advanta' mrs and toi-ry oils are Ablended and are Ol.di geously be all or aportion .of'thehot tar or pitch Y mamy Shipped from the Coke Oven O1. other com produced by subsequent distillation of the gases distiiiation plant to a tar disuiiaiionvpmnt for after they have been defined' thereby Obtamng distillation and separation of the oils, and the acoupter'current Scrilbbmg. of the gases and (.115- 90 pyoduobion of .pitches of varying quality Ham tillation of the tar, if desired; othery materials dling costs, freight charges and distillation cost, may likewise be used as scrubbing meda' including fuel. capitaliand maintenance expense The materia; to be distilled according t() the for the special equipment required for distillapresent mvenmon may be coal tar produced at I mm add to me Cost f coke oven plants, or gas house tar produedet 4J products' o the tar dlstmatmn gas Aretort plants (vertical, horizontal or in- 95 The I. 'Y cliiied),water gas tar, or tar from another source. me tho dpasd nzp 33212511502; pgesta] tlpllv ed. Such tars frequently contain a considerable per- .t l HUI N O Ol centage of water intimately admixed or combined pl c 1 1S l 1 ed by mem of hot gases from Coal therewith articularl where-water or ammonia .1.1. gasification or carbonization operations, which liquor is emloyed foryseparatng and condensing 10o SICS have been gleaned at the required tempelfa the tar constituents from the coal distillation or tuie'by a sciubbing treatment, The present iiiother gases and such tars may,l if desired be veiition makes use oi" heat contained in high teni'- dehydrated before being distilled according to peiature coal carbonization gases, such as gases this invention' .:i from the collector main of a coke oven battery, The gases which are employed, according to by'enDOl/mg them f0r dlstllling tar. tal' Oil 01 the present invention, for` distillation arehot pitch while they are still at a high temperature gases produced by a coal carbonization or gasiand after they have been subjected vto a cleaning fication operation, and which are cleaned or par- 1 Opclatlon. y tially cleaned prior to use for distillation. The 10 The cleaning of the gases at a high temperature hot gases, whichv are subjected to cleaning and gases or hot retort gases or hot water gas, etc. In the case of coke oven gases, for example, the gases escape from the coke ovens at a high'temperature,`e. g., from 600 to '700 C. or even higher in some case, and can be cleaned at a temperature sufficiently high to permit effective distillation therewith after cleaning. High temperature gases are also formed and are withdrawn from gas retorts, water gas retorts, producers, etc. and can be used for distilling after cleaning.

Coal carbonization gases when they leave the ovens or retorts, etc. in which they are formed contain entrained solid and liquid impurities which it is the object of the scrubbing treatment' to remove to a greater or less extent. If the scrubbing medium employed is of approximately the same temperature and composition as the entrained liquid impurities, which it is desired to remove, the scrubbing will be effected without material alteration ofthe scrubbing medium or of the gases treated, except by removing from thegases and adding to the scrubbing medium the entrained particles removed from the gases by the scrubbing operation. If the scrubbing medium is colder than the gases treated, the gases will be cooled and condensable constituents will be thrown out of the gases and removed from the system with the residue from the scrubber, while the scrubbing medium will be heated and if low boiling constituents be present in this medium they may be volatilized and carried over with the gases to the still. If the scrubbing medium utilized is at a temperature higher than the temperature of the gases, the gases may be heated and partial volatilization of entrained liq'- uid impurities may result although if the vscrubbing medium contains material which will be volatilized by the hot gases no increase .in temperature of gases may result due to expenditure of heat as latent heat of vaporization of the material evaporated.

Although in a generallway the entrained` liquid impurities are in equilibrium with the gases, these 1mpurities which are carried forward from the ovens, retorts, etc., are present as fine globules in the form of a mist.V Prolonged contact of these entrained globules with the hot lgases would bring about a condition of equilibrium between the gases and the composition of the globules, but it is the object of this inventionto scrub the gases at a high temperature, preferably as quickly as possible after the gases leave the coal carboniza- .tion apparatus, and equilibrium conditions may not be established in so short a time.

Tar, preferably heavytar, or pitch, preheated where practical, is well adapted for use in scrubbing the gases Ain carrying out the invention.

In order to avoid unnecessary cooling of the gases and consequent condensation vof vapors carried by the gases and loss in the amount of heat available in the gases for distillation purposes, the equipment through which the gases pass on the way from the coal carbonization or gasification apparatus to the still as well as the still itself, may advantageously be insulated, and the distance between the coal carbonization apparatus and the scrubber on the one hand, and the scrubber and the still on the other, kept at the minimum which practical operation permits. In many cases, particularly when hard pitches are to be made or high boiling oils to be distilled, gases should be used at high temperatures. In such a case the gases will be subjected to little, if any, spraying in the collector main, and all Linealesl equipment through-which the gases pass tothe still will be well insulated.

Although the invention is of broader application, it will be described more particularly in connection with coke oven operation. The gas employed for the distillation may be cleaned at a temperature not greatly below that at which'it leaves'the coke oven, or the gas may be cleaned at a somewhat lower temperature. The temperature of the gas and the character of the condensable components entering the still may be regulated by the treatment to which it is sub- A jected during the scrubbing treatment and prior to its use in the distillation operation.

According to this invention the gases are used for distillation while at a temperature as high as 300 C. or 400 C., or even as high as 500 C. or higher, although larger amounts of gases at lower temperatures can be employed for effecting distillation oi the tar.

The temperature and amount of the gases'used may be regulated according tothe distillation which is to be carried out. If tar is to be distilled only to a limited extent, the temperature of the gases used in the distillation need not be as high, or the amount of the gases employed need not be as great as when the tar is to be distilled to a greater extent to produce a harder pitch.

Where maximum conservation of the heat oi' the gases is desired in the use of coke oven or gas retort gases, the scrubber may be placed upon the block of ovens or retorts,

case the scrubbing medium, after being used to scrub the gases may be allowed to flow down linto the collector main to flush it. The still may be placed upon or adjacent to the block of ovens or retorts. In using other gases a similar relation between the units may be maintained as far as possible. 1

In the operation of a coke oven the gases produced are not ofuniform composition. At the or even upon .the collector main f or the gases. In the latter percent of the operating time under normal conditions, contain a less percentage of condensable constituents thanl the richer gases given of! during the iirst part of the distillation, and are known as lean gases. The tars contained in the lean gases contain higher percentages of free carbon than do the tars in rich gases. There is in many cases an advantage in using either the rich gases or lean gases separately and after cleaning, in distillation of tar. oils, etc., according to the present invention. For example, lean gases are capable of taking up a greater quantity of oil and other vapors per unit volume than an equivalent amount of a rich gas which already contains moreI volatile constituents than does the lean gas, both gases being at the same temperature; while richer gases contain a larger amount of condensable vapors which admix with the distilled vapors and are condensed therewith.

In order to take advantage of either rich or lean gas separately for use in distillation, the coke oven may be equipped with two collector mains, each of which is adapted to be thrown into communication with the uptake pipe from each of the ovens in the battery to which the collector mains are. connected through a system of valves. As an example, during the rst of the distillation operation in any one oven, this oven collector main which is in communication withy the scrubber and still. By the usual rotation o f the ovens in a battery of' average size there will at all times be a fairly continuous and uniform production of lean gases, so that the quantity and temperature of the gases passing through the scrubber and still will be fairly uniform at all times. Richv gases will, in many cases, be desired for distillation, and can be utilizedby my invention. Y

Carrying out the distillation according to the present invention, the coal distilling gases, after preliminary cleaning at a high temperature, are

brought into heat-interchanging relation with the tar to be distilled and are advantageously brought into direct and intimate contact with the tar. This intimate contact of thetar and gases can be eiected in various ways.' and the .distilling operation can be carried out either as a batch operation or as a 'continuous operation. Tar or pitch to be distilled can, for example, be atomized or sprayed into a current of the hot cleaned gas, thereby bringing the tar or pitch particles into .intimate contact with the hot gas andvheating these particles to a suilicient temperature to distill off volatile constituents to a greater or less Y extent. Instead of spraying or atomizing the tar or pitch into a current of hot cleaned gas, a current of the gas may-be forced through a b of tar, tar oil or pitch, thereby heating and agi--` tating it and effecting distillation of the desired constituents therefrom, which vaporized constituents are carried by the escaping gases.

The distillation can likewise be effected in a counter-current manner, for example, by causing tar or pitch to fiow downwardly through a baiile tower or other apparatus in which an upward flow of the hot cleaned gases is effected, so that the downwardly flowing tar or pitch is pro` gressively heated and distilled, or the hot cleaned gases may be passed over the surface of a body of tar or pitch, for instance in a closed tank. In this latter case, it will be desirable, though not essential, to agitate the contents of the tank to keep fresh surfaces exposed to thel gases.

The scrubbing may advantageously be effected by the hot tar or pitch residue from the still. The temperature of the scrubbing liquid is regulated so that the temperature of the gases eni tering the still is that desired for the distillation which is to be accomplished in the still; In order to Vinaintain the gases entering the still at a sufficiently high temperature, it may bedesirable at timesto pre-heat the scrubbing liquid to a high temperature, e. g., to around 250 or 300 C. or higher. This may be done by passing the liquid in heat-interchanging relation with hot gases resulting from the distillation process or by applying steam or other heat as from coinbustion vgases to the pipes conveying the scrubbing medium to the scrubber. The-scrubbing operation can be modified by regulation of the kind of scrubbing medium used and by l.rt-:gulating its temperature. By using a scrubbing medium ccntaining oils that will be-yolatiiized during the scrubbing the degree of enrichment of the gases used for distillation may be regulated. If the scrubbing medium contains no material that will volatilize during the scrubbing operation, the

hot gases will not be enriched. In some cases volatile materials contained in the gases may actually be absorbed by the scrubbing medium, thus reducing the enrichment of `the gases as `respects condensable oils. l

vThe tar or other material entrained in rich gases 'contains a lower percentage of free carbn than does that from lean gases. Thus the character of the residue from the scrubber as respects free carbon content can be controlled byusing for distillation gases carrying as entrained material that tarry matter containing the appropriate percentage of free carbon.

Depending upon the extent to which the distillation is carried, substantially only the light oils may be removed from the body ofl material to be distilled leaving a heavy tar or light pitch in the still, or by ycarrying the distillation further, heavier constituents will be volatilized and subsequently recovered from the gases, and a still heavierpitch will remain as a residue in the still. Y

The distillation can be accomplished in numerous ways'. For example, a large volume of relatively 'low temperature gases may be used, or a smallerv volume of relatively high temperature gases may be used. The material. to be distilled may be preheated if desired before being brought into contact with the gases. l

The gases escaping from the distilling voperation will carry in vapor form the constituents volatilized from the tar, oil or pitch and will contain in addition thereto such of the vapor constjituents carried by the gases entering the still as have not been removed by condensation as a result of the cooling produced by contact of the gases with the material being distilled. In the loo case of hot coke oven gases employed for the while it is still hot before itl has had opportunity to cool, a saving in heat may be eifected. i The gases from the-still eanlbe treated for the condensation and recovery of the desirable constituents contained therein as well as for the recovery of ammonia carried thereby. Where only a portion of the-gases from'the coal carbonization. apparatus are passed through the still, those gases which are enriched by passing through the still can be treated in a separate recovery system and the oils condensed therefrom will be a mixture of the oil constituents normally in the gases and those added to the gases duringfthe distillation. whereas the condensate from the remainder of the system will contain only the usual coal earbonization products. The gases can, however, be treated in the same recovery system with the remainder of the gases produced by the coal carbonization.

Several stills may be employed in series so that the gases leaving one still will pass through an other still in which available heat of the gases may be used for distillation.` Fresh tar or pitch may "be supplied to each still, or the residue from one still may be fed to another-still, in which case it may be desirable that the flow of gases and material to beV distilled will be caused to i'iow and hot gases, e. g., gases of the contents of the stills. pumped through two or more stills in succession from a coke oven bat-i tery may be. bubbled up through the contents of each still, the gases being`passed through the stills in a direction countercurrent to the iiow of the oil through the stills. The first still may serve as a scrubber, or the gases may be cleaned prior to their use for distillation or progressively.

cleaned as they pass through the stills. The gases leaving the last still will be clean and contain oil vapors which, on cooling, will be obtained as clean oils. The oil will be distilled and a progressively higher boiling residue will remain in each still. The residue taken from the still into which the hottest gases pass may be a heavy tar or pitch. By such a countercurrent flow the hottest gases are brought into contact with the heated high boiling residuevfrom-preceding stills. In a coke oven plant where several batteries of coke ovens are operated, the rich or lean or total gases from one battery may be cleaned at a high temperature and employedY for distilling tar from the other batteries, or a part of the gases from one battery may be so employed. The gases used in the distillation may be only a portion of the gases collected in the collector main and may be taken oi one end of the collector main or all the gases passing through the collector main may be utilized, eg., by taking them oli the centerbox according to the customary practice. A prod- `uct other than a coal tar product, can be distilled and the condensable constituents recovered in a separate recovery system without contaminating the balance of the coal tar products produced.

In some casesit may be desired to regulate the character of the residue of distillation or of scrubbing, as respects free carbon content, or as respects type of oil remaining in or added to it.

This may to a greater' or less extent be accomplished by using richl or lean or intermediate gases for distillation. Rich gases contain tar with a relatively low free carbon content and they contain als`o oils of lower average boiling point and lower specinc gravity than do lean gases. vRich. gases contain a greater amount of tar than do lean gases. As the gases get leaner, the amount of tar contained decreases, the percentage of free carbon in the tar increases, the amount of oil contained decreases, and its speciiic gravity and average boiling point increase. Since in the scrubbing and distillaton operations more or less of the tar. contained in the gases will be retained in the scrubbing or distillation residue and more or less of the contained heavy oils will be condensed and retained in the residue, lthe character of the residues may to some extent be controlled by choosing the proper gases for distillation. Such gases may be rich, lean or intermediate gases.

Where the distillation is carried out as a batch operation, for example, by bringing the hot cleaned gases into intimate contact'with tar to -be distilled, the' tar is progressively heated by the hot gases and the lighter constituents are progressively removed therefrom until the' distillation has been carried to the desired point, after which the operation can be discontinued, and the residue withdrawn, and the still recharged with further tar to be distilled. In the case4 of com tinuous distillation, the operation can be controlled by regulating the time of contact .of the tar with the gases, or the intimacy of contact, or

Athe temperature of the gases, or the amount oi? Atarry oil may be the gases, or a.V combination of these, so that the desiredv degree of distillation can be effected.

The invention will be further described in connection withthe accompanying drawings illustrating several forms of apparatus embodyingv the inventionv and adapted for Athe practice of the process of the invention, but it is intended and will be understood that the invention is illustrated thereby but is not limited thereto.

In the accompanying drawings,

Fig. 1 shows in a somewhat conventional and diagrammatic manner a plan view of a coke oven battery showing apparatus for the distillation of'` tar by means of the hot cleaned coke oven gases;

Fig. 2. is an enlarged view of the scrubber of Fig. l;

Fig. 3 is a plan .view of a modified' form oi apparatus in which two collector mains are shown4 together with separate apparatus for scrubbing the hot gases; l

Fig. 4 is an enlarged detail showing in crosssection the relation of the two collector mains of Fig. 3 to each other and the coke oven;

Fig. 5 is an elevation partly in cross-section showing in greater detail the stili shown in Fig. l; r

Fig. 6 is a cross-section'of the still shown in Fig. 5;

Fig.. 'i' is a plan view of Fig. 5;

Fig. 8 shows a modified form of still which may be substituted for the still shown in the preceding figures; and

Fig. 9 showsl another form of still.

In the drawings, part of the coke oven battery is shown at l, with the usual uptake pipes 2 for the escape of the coke oven gases, and collector main 3 connected withthe uptake pipes. The center-box for the collector main is shown at 4. The coke oven gases escape from the collector main and center-box through the cross-over main 5 to the cooling and condensing system indicated conventionally as two condensers 6 and 7. From these condensers, the gases pass through the pipe 8 and the usual tar trap (not shown) to the exhauster 9, and then through the gas outlet pipe lu to ammonia saturators and benzol scrubbers, or other apparatus (not shown).

In the collector main and goose-necks sprays 11 are provided for regulating the the gases to a greater or less extent. The liquor admitted to the collector main, which is not voiatilized, together with the condensed tar, collects in the center-box 4, while the gases with some entrained tar and liquor. and uncondensed the still shown in temperature of vapors pass through the cross-over main 5. The

liquor and tar may be drawn off from the centerbox 4 through the pipe'12 to the decanter 13. Ammonia liquor is decanted oi to the receptacle 14 and tar is drawn off into the tank 15. The 135 liquor and tar may instead or in addition be drawn off through line 12 to decanter not shown. The gases used for distillation are shownin the drawings as being drawn off from the end'of the collector main through the pipe 16,'through l lwhich they are conducted to the scrubber 1'1 where they are scrubbed with liquid sprayed through the sprays 18, and after being thus more or less cleaned are passed through the pipe 19 to the still 20. Instead of locating the collector main, scrubber and still in the relation shown, in actual operation they may advantageously be brought closer together. The scrubber and still may-be located upon lor closely adjacent to the block of ovens. The scrubber may even be situtrainment of non-volatilized contents ated upon the collector main with the still placed, 'adjacent thereto upon top of the battery.

`main 5 by being by-passed through 23 and the" main 24 to the usualcross-over main 5. The` gases are drawn through the still by the ex` hauster 25. Bafiies (not shown) may be provided at the gas outlet from the still to prevent enby the gases.

In the drawings,`the condensers 6 and 7 are shown equipped with decanter 30, and the condensers 21 and 22 with a decanter 31. From these decanters ammonia liquor is drawn o into the ammonia liquor storage 32 and tar is drawn' off into thetank 33 and oil into tank 34. Two oil fractions may be collected by running the condensate from 21 and 22 to separate decanters.

Line 21 is provided to allow this. The second` decanter is not shown. u

The sprays 11 in the collector main and goosenecks may be supplied with ammonia liquor irom any source through the pipe 36l or the pipes 36 and 36' may preferably be`supplied with tar from the tank 33. Tar from the collector main after separation of the ammonia liquor may be supplied to the scrubber through the pipe 37 and to the lstill through the pipe 38. Residue from the still may be supplied by'pump 39 to the sprays 18 to be used as a scrubbing medium in the scrubber by line 40 lor may be passed to the storage tank 41.

The liquid entering the sprays 18 is passed through heat interchanger4 42 in which the temperature ci the liquor may be regulated, if desired.

`:Residue from the scrubber may be withdrawn to the tank 43 from which it may be recirculated through the scrubber by means of pump 45, pipe 34 and the sprays 18 in the scrubber. In some cases it may be desirable to pump the eilluent.

from the scrubber into sprays 11. Pump 45 and lines 44, 36" and 36 provide for this.

Tar from an outside source such as gas-house tar, etc., may be supplied tothe sprays in the collector main through the pipes 46, 36 or 36 or to the scrubber through thepipe 47 or to the `still through the pipe 48. -The liquor passing to the still passes through the heat interchanger 49.

When operating as a continuous process, the coal tar product from one vessel may be supplied directly to another appropriate vessel without rst passing to a storage tank.

In their passage from the ovens to the scrubber, and in their passage through the scrubber itself, the treatment of the gases is so regulated that the gases upon leaving the scrubber and entering the still are at a suiliciently high temperature to eect the desired distillation in the still. Although in general the gases pass from the ovens through collecting means, such as a collector main, in which they may be subjected to regulated spraying, such collecting means may be omitted and the gases from several ovens may be passed directly intol scrubbing means, located preferably upon the ovens and from there into the still.

I! the gases entering the still, still contain entrained impurities, these will be removed, at least to some extent. bv the contact of the gases with of the still 5v the contents of the still` Heavy constituents present as vapors in the gases entering the still may be condensed, while the distillation will cause volatilization ofthe lighter constituents of the ycontents of the st which will be admixed and carried along with the gases from the still, producing an enriched gas. By subjecting, thegases escaping lfrom the-still to separate cooling and condensation, a. relatively clean oil can be'directf 1y obtained as in the storage tank 31, while by returning the gases and admixed vapors to the main condensing system the condensable constituents can be recovered, as in the decanter 30, without the need of separate, condensing equipment, and the resulting products will be relatively cleaner than thosenormallyobtained.

According to one preierred method of operation several batteries of a coke oven plant, or a portion of the ovens in a coke oven battery are i operated in the usual way, that is by spraying the gases in the collector main withammonia. liquor or .taran'd ammonia liquor and cooling the resulting gases in direct or indirect condensers locoated over beyond the cross-over main. The drawings illustrate one battery so equipped that the gases from a portion of the ovens may ybe treated in the usual manner. The gases passing from theiovens to the left of the center-box in Fig. 1 v(or by locating the valve 2' to theright of where it is now shown, all the gases from the ovens to theleft of the center-box and some of the ovens to the right oi the center-box) will be sprayed with ammonia' liquor or ammonia liquor and tar from the pipe 36.A The gases passing through the cross-over main 5 are sprayed with 110 water or ammonia liquor in the condensers 6 and 7. Tar such as that thrown down in the collector main by the usual method of spraying operation here described is supplied to the still, 20 through the pipe 48. Residue from the still 115 while still hot is supplied to the scrubber through the line 40. In some cases residue from the scrubber may be used to spray the gases from the ovens near that endv of the collector main toy which'the main 16 is connected. This affords a 120 counter-current ilow of gases and tar, or oil. The gasesin the end of the collector main from which the gases forA distillationl are taken are, Where high temperature gases are required,`sub jected to minimum cooling in order that the heat 2l of the gases may be utilized in the still and yet the spraying must be suilicient to prevent objectionable deposit of pitch in the collector main. ToI prevent formation of objectionable amounts of pitch here the heavy tar or pitch from the 130 scrubber may in some cases' be cut back with lighter tar such as some of that which collects in the container 15. Tar from 15 or tar and ammomia liquor or ammonia liquor may be iiushed into the end of main through line 37. Residue 135 from the scrubber may also be flushed in through` 37'. In such cases sprays 11 in the main adjacent to oitake line 16 may be shut o if. This will prevent undue cooling of the gases going to 16. The

balance of the tar drained from the collector the collector main of a Semet-Solvay coke ovenl with tar or pitch by means of sprays 71. Baines '12 are provided for removing a large portion of the entrained spray from the gases which leave the tower by the pipe '73. Non-volatilized constituents collect in the bottom of the tower and may be drawn oi through the pipe '14 or may be recirculated by the pump through the pipe 76 and again sprayed into the gases through the sprays 7l..y instead of recirculating the tar or pitch, the'nozzles may be supplied with fresh tar or pitch through the pipe 78. Other types of stills, in which the gases and liquor are brought into intimate contact, may be substituted for the still 20 of Fig. i or stili 320 of Fig. 3.

The amount'o distillation which takes place within the still will depend upon the quantity and temperature ci the tar and gases supplied to the still and upon the character of the product to be distilled. The het coke oven gases for the still may be drawn ci? from the end of the collector main or at the center box as shown in the drawings, or from any other part of the collector main or other collecting means, or' the het gases may be tapped ofi any other part of the apparatus from which gases of sulicient temperature may be obtained. Ii spraying is eliminated or kept at a minimum in one portion of the collector main, and gases from that portion of the collector main are led' to the scrubber and then to the still, these gases may be at a temperature not greatly below that at which the gases leave the coke ovens. scrubbing with tar or oil in the scrubber may tend to reduce the temperature of the gases, but by' preheating the scrubbing mediumv or by using a hot scrubbing medium decient in volatile oils. or by regulating the quantity of the scrubbing medium,'the dropin temperature may be reduced or regulated.

Although the operation has been described and shown as a method ot removing hot gases from collector main, and scrubbing the gases at high temperature and using them for distillation pur'- poses, it is to be understood that the operation may be adapted to coke ovens of other types and that all the gases from a coke oven battery may be so utilized instead of withdrawing only a part of the gases as in the method here described in detail.

Tars or pitches or various grades may be used as a scrubbing medium4 and, by distilling in the still, other tars or pitches than those recovered from the hot gases used for distillation purposes, composite heavy ta'rs or pitches will be recovered in the still and composite oils willI be recovered after scrubbing.

I claim: l. The process of distilling heavy hydrocarbon materialvin liquid form which comprises removing entrained impurities from hot fresh coal` gasification gases, bringing the hot treated gases and the material to be distilled into direct contact while the materiel is maintained at a distillation temperature, the removal of the entrained impurities from the gases 'being effected at such a high temperature that the treated gases are at a. temperature above the distillation temperature of the material when brought into contact with the material so that heat is supplied to the material from the gases.

2. The processor distilling tar which comprisesA removing entrained pitch particlesv from fresh hot coke oven'gases resulting from the distillation of coal 'in a 'coke oven and supplying heat to the tar whiieftiie i'a; is at a. distillation temperature by bringing the treated gases into direct contact with4 the tar,"v the entrained pitch particles being' removed" from the gases at such 1 I a hightemperature that when the gases are subsequently brought into contact with the tar they are above the distillation temperature of the tar,

and then cooling the gases and vapors resulting Ifrom the distillation of the tar to recover dis.

tillate comprising constituents' distilled from the tar and constituents originally present in the hot coke oven gases.

3. A process for distilling coal tar hydrocarl bons in liquid form which comprises removing en'- trained impurities' from hot fresh coal distillation gases, and bringing the hot treated, and material to be distilled into direct contact while the material is maintained at a distillation temperature, the removal of the entrained impurities from the gases being effected at such a high temperature that the treated gases are at a temperature above about 300 C. when brought into contact with the material and heat is supplied to the material from the gases.

. STUART P MILLER.. 

